Lateral adjuster for surveying instruments.



No. 696,401. Patented Apr. I, |902.

C. L. BERGER.

LATERAL ADJUSTER FR SUHVEYINE INSTRUMENTS.

(Application fled Sept. 25, 1901.) (No Model.)

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artnr LATERALADJUSTER FOR SURVEYING INSTRUMENTS..

SPECIFICATION forming part 0f Letters Patent N0. 696,401, dated April 1,1902. Application filed Septemberz, 1901. Serial No. 76,516. (No model.)

To @ZZ whom it may concern..-

Be it known that I, CHRISTIAN L. BERGER, a citizen of the United States,residing at Boston, county of Suffolk, State of-Massachusette, haveinvented an Improvement in Lateral Adjusters for Surveying Instruments,of which the following description, in connection with the accompanyingdrawings, is a specification, like letters on the drawings representinglike parts.

Myinvention relates to the base portion of a surveying instrument, andis more particularly adapted to mining-transits, being intended toprovide means for quickly shifting the transit horizontally after it hasbeen properly leveled and adjusted without disturbing said adjustment. jIn general, surveying instruments have been moved laterally relativelyto the tripod in two ways, one way being to move the upper part of theinstrument relatively to the base and the other way being to move theinstrument and its base bodily, the former, however, resulting inplacing the telescope and adjacent parts eccentric to the vertical axisof the instrument, and hence in that respect in improper position forusual work, especially mining-work, and the latter, al- 'though notsubject to the last-mentioned objection, being, however, of suchconstruction that precision of movement and maintenance of theinstrument adjustments could not be relied upon. AccordinglyI havedevised the special means, which are more fully set forth in thefollowing description, for enabling the operator to be sure at all timesthat when once adjusted and leveled the instrument, although movedlaterally, will maintain its said adjustments, and to know also that thelateral movement takes place with perfect precision, as intended.

In the drawings, in which I have illustrated a preferred embodiment ofmy invention, Figure l is a perspective view of a usual surveyinginstrument having one form of my invention applied thereto. Fig. 2 is anenlarged central vertical section of the most complete form of myinvention. Fig. 3 is a right-hand side elevation thereof, parts beingbroken away. Fig. 4. is a sectional view similar to Fig. 2, showing asimple form of the in vention. Fig. 5 is a vertical cross-sectionaldetail on the line 5, Fig. 4; and Fig. 6 is a bottom plan View, partsbeing broken away.

For convenience of illustration I have shown a portion of a usualtransit A, mounted on a4 usual tripod a, the former containing a usualpost a', leveling-screws a2, base-plate a3, centrally apertured at co4to permit usual lateral adjustment of the base a5 of thesupporting-post, and the tripod is provided at its upper end in usualmanner with a threaded shoulder or ring as. Preferably the threads ofthe plate a3 correspond to the threads of the ring a, so that whendesired the intermediate device (which constitutes my invention) may beremoved and the plate a3 may be screwed onto the ring a6 in its usualposition. My invention, as already stated, resides in providing specialmeans between the plate a3 and the tripod-ring a6 for accuratelyshifting the superposed instrument one way or another precisely asrequired, this feature being of particular value in mining-work belowground, although I do not limit the same to this use.

In mine-surveying the work is sometimes done in the dark or partialdarkness and the leveling of the instrument by the aid of a faint light,and proper adjustment thereof consumes a great deal of time, patience,and skill, so that when it is once accomplished it is of peculiaradvantage to retain the adjust ments. For example, in getting the rangeof two plumb-lines, which may be suspended in usual manner from the topof a vertical shaft, the plumb-bobs being held stillin buckets ofmolasses or in other well-known manner, the surveyor first sets up histripod as nearly in correct position as he can judge and as may be4permitted by the situation. He then gets the instrument more accuratelyin line by means of the telescope, and, having done so, levels theinstrument; but in doing so he throws the telescope out of line. If,now, the instrument is of the ordinary kind, as shown in the upperportion of Fig. l, he must slightly loosen the leveling-screws a2, so asto shift the instrument-post a5 relatively to the plate a3, and therebybring the telescope back approximately into line.. This, however, hasdestroyed the accurate leveling of the instrument, and therefore it mustagain be leveled. Bearing in mind that this IOO all takes place incomparative darkness with only at least a glimmer of light, it will atonce be seen that this destroying of the proper leveling of theinstrument becomes very serious. To prevent this difficulty, I provide aguideplate Z1, provided centrally with threads b', fitting the ring a,so that it may be screwed rigidly in place, and on this plate I mount aslide-plate b2, which may be provided in the simpler form of myinvention with an annular flange b3, threaded to correspond to the ringa6 for receiving the base-plate a3 of the instrument. In this case theinstrument has a lateral movement in one direction by reason of theslide-plate b2 moving over the guideplate b. Preferably, however, alateral movement is provided also in an opposite horizontal direction,this result being accomplished, as herein shown, by providing on theupper side of the slide-plate b2 a guideway b3, similar in generalconstruction tothe guideplate b, and on this guideway b3 is fitted asecond slide-plate b4, which is provided with an annular threaded flangeb5 for receiving the base-ring c3 of the instrument.

Referring further to the consti-notional details of the device, it willbe seen that the edges of the guides b b3 are beveled or oblique andthat the slide-surfaces of the plates b2 b4, which bear on said obliquesurfaces, are also correspondingly oblique, thereby insuring apermanently accurate it and also providing a construction which makes itimpossible for drib or moisture to reach the bearing-surfaces. Absoluteaccuracy of adjustment is secured by providing bearing-'screws b in ltheslideplates to bear against the adjacent top surface 'of the guides, asclearly shown in Figs. l and 5.

On its under side the slide-plate b2 is provided with retaining-screwsb', which engage the under sides of the adjacent edges 'of the plate b,and for the same purpose screws bs are provided to engage a narrowflange bf of the plate b4 when the latter is employed. In

this manner the instrument may be kept in l true position precisely asrequired. At one or b'oth ends, the. latter giving the greatestprecision, I provide operating screws b, i working in the threaded endsZ910 of the plates b and b4 and bearing against apertured projectionsZ112 from the superposed slides, these screws being provided withsuitablethumbnuts or other turning means Z213. Preferably, also, eachscrew carries an accurately-spaced indicator bm, said indicator, asherein'shown', having points 1915, located forty-five degrees from eachother, for coperation with a projection bw on the adjacent slidingmember, so that in the comparative darkness the operator may knowprecisely how far to one side or the other he shifts his instrumentsimply by feeling the number of points of the indicator which he turnspast kthe projection 1916.

From the above description the operation of my improved lateral adjusterwilll be readily understood. The operator wishin g to do undergroundwork simply takes his usual instrument and separates the upper portionat the base-plate a3 from the tripod and then screws onto the latter myattachment and places the upper part of the instrument on top thereof,screwing the base-plate a3 on the liange b5 in case the more completeform of the device is used or on the ring b3 in case the simpler formshown in Fig. 4 is employed. Having adjusted his instrument in usualmanner, as required, he now shifts the entire instrument with precisionto the left or right, forward or backward, as the case may be, bysimultaneously turning in reverse directions the opposite thumb-screwsZ113, or one of them only in case the other is omitted,and by countingthe number of points Z915 which turn past his thumb resting on theprojection 1916 he knows the exact distance to which the instrument isshifted. In case he should desire to tip the instrument slightly one wayor the other or take up any wear of parts, he correspondingly adjuststhe screws b or such of them as may require it.

While I have herein shown and described my invention in all itspreferred details, I wish it understood that, excepting as otherwiserequired in the claims, I do not limit my invention thereto, as manychanges in construction and arrangement of parts may be resorted towithin the spirit and scope of my invention.

Having described my invention, what I claim as new, and desire to secureby Letters Patent of the United States, is

l. A lateral adjuster for mining-transits, comprising a guide-plateprovided centrally with means for rigidly securing the same on a vusualtripod, a slide-plate mounted thereon, said two plates being mutuallyprovided with cooperating ways for maintaining accurate direction ofmovement, a thumb-screw in engagement with said two plates foraccurately moving the top plate on the bottom plate, and means formounting above said top plate a mining-transit- 2. A lateral adjusterfor mining-transits, comprising 'a 'guide-'plate provided centrally withmeans for rigidly securing the same on a usual tripod, a slide-platemounted thereon, said two plates being mutually provided withco'peratingv-'ays for maintaining accurate direction of movement, athumb-screw in engagement with said two plates for accurately l movingthe top plate on the bottom plate,

said top plate being provided on its upper side with guideways extendingtransversely to the direction of movement of said plate on theguide-plate below, a topmost guide-plate mounted on said guideways andshaped on its under surface to t on said guideways, means for movingsaid topmost plate on said guideways, and means above said topmost platefor securing thereto the instrument proper.

3. In a mining-transit, means located between the instrument proper andthe tripod IOC IIO

rigo

for shifting the instrument bodily in one direction in a horizontalplane, and means for similarly shifting said instrument bodilyin adirection transversely thereto.

4. In a mining-transit, means located between the instrument proper andthe tripod for shifting the instrument laterally in a horizontal plane,and means angularly shaped to indicate, by feeling, the extent of saidlateral movement.

5. In a mining-transit, means located between the instrument proper andthe tripod for shifting the instrument laterally in a horizontal plane,said means includingastationary part, a thumb-screw, and an indicatorrotative therewith containing coarse spacingpoints for enabling theoperator to tell, by feeling, the extent of rotation of said screw byreference to a relatively stationary part.

G. A lateral adjuster for mining-transits, comprising a guide-plateprovided centrally with means for rigidly securing the same on a usualtripod, a slide-plate mounted thereon,

said two plates being mutually provided with coperating ways formaintaining accurate direction of movemenua thumb-screwin engagementwith said two plates for accurately moving the top plate on the bottomplate, an indicatorjcapable ofreadily indicating by feeling, carried bysaid thumb-screw for indicating the extent of rotation thereof, andmeans for mounting above said top plate a mining-transit.

7. A lateral adjuster for mining-transits, comprising a guide-plateprovided centrally with means for rigidly securing the same on a usualtripod, a slide-plate mounted thereon, said two lplates being mutuallyprovided with cooperating Aways for maintaining accurate direction ofmovement, a thumb-screw at each end of and in engagement with said twoplates for accurately moving the top plate on the bottom plate, andmeans for mounting above said top plate a mining-transit.

8. A lateral adjuster for mining-transits, comprising a guide-plateprovided centrally with meansforrigidly securing the same on a usualtripod, a slide-plate mounted thereon, said guide-plate having itsopposite sideedges beveled, and said slide-plate having at its oppositeedges depending portions beveled on their inner sides to rest on thebeveled edges of the guide-plate, means retaining said two platespermanently together, independentlyoperable adjusting devices foradjusting the bearing-surfaces of the two plates with relation to eachother, positive means for accurately sliding the top plate on the bottomplate, and means for mounting the instrument proper above the top`plate.

H 9. A lateral adjuster for mining-transits, comprising a guide-plateprovided centrally with means for rigidly securing the same on `a usualtripod, a slide-plate mounted to slide on said guide-plate, guidingmeans for Inutually guiding said plates in relative longitudinalmovement, a transit proper mounted on said slide-plate and comprisingusual telescope-leveling devices, dac., and meansfor positively movingthe top plate on the bottom platete any predetermined extent required.

-In testimony whereof I have signedmy name to this specification in thepresence of two subscribing witnesses.

CHRISTIAN nBEReER.

l Witnesses:

GEo. H. MAXWELL, GEO. W. GREGORY.

